Oil circuit breaker comprising an extinguishing chamber for high voltages



Aug. 6, 1963 w. PucHER 3,100,249

OIL CIRCUIT BREAKER COMPRISING AN EXTINGUISHING CHAMBER FOR HIGH VOLTAGES Filed Dec. 1, leso INVENTOR @Muff @M45/f United States Patent O 3,100,249 OIL CIRCUIT BREAKER COMPRISING AN EXTEN- GUISHING CHAMBER FGR HIGH VOLTAGES Walter Pucher, Ekvagen 3, Ludvika, Sweden Filed Dec. 1, 1960, Ser. No. 73,128 Claims priority, application Sweden Dec. 16, 1959 2 Claims. (Cl. 200-150) In oil circuit breakers it is known to use an extinguishing chamber in which the oil yforced aside by the arcing gases during the rst part of a breaking action increases the gas pressure in a closed space above the oil surface in a pressure accumulating chamber. At a predetermined distance between the contacts of the circuit breaker an outlet channel for oil in the pressure accumulating chamber is opened and this oil may now be forced out through the outlet channel against the arc by the gas pressure in the closed space as the breaking current approaches zero.

Experience has shown that the length of the arc necessary `for the breaking increases with the breaking voltage. Together with the length of the arc, the energy, the amount of gas and the compressive stress generated in the circuit breaker also increase. To keep the pressure within endurable limits and to obtain an electively extingushing ow of gas along the whole arc, the present invention relates to an oil circuit breaker comprising an extinguishing chamber for high voltages immersed in oil. An arc ichannel is arranged in the extinguishing chamber and a movable contact can be passed through the arc channel to a stationary contact.

r[he invention is characterised in that along the arc channel at least two pressure accumulating chambers partly -iilled with oil are arranged after each other, each communicating with the arc channel through a connecting channel. At least one outlet channel connects the arc channel and a pressure accumulating hamber 'with the space outside the extinguishing chamber. The outlet channel can suitably be arranged in the space between two adjacent pressure accumulating chambers.

At a breaking action the arc is drawn through the arc channel by the movable contact, which at the same time starts the flow of gas against the arc by opening one outlet channel after the other. Further, due to the number of open outlet channels being proportionally increased to the length of the arc this extinguishing chamber has good qualifications to handle a short circuit which appears during a breaking action. The extinguishing chamber also breaks alternate current of a frequency lower than 50 c./s. more easily than, e.g. a contraction chamber.

The outlet channels communicate with openings in the outer wall of the extinguishing chamber. Openings belonging to outlet channels from adjacent pressure accumulating chambers have in relation to each other been displaced around the arc channel. This has been done in order to prevent the arc flames through said openings from coalescing outside the extinguishing chamber.

In order that the pressure shall not be too high in the extinguishing chamber the arc channel may be connected by pressure unloading channels arranged `in the proximity of the stationary contact to the space outside the extinguishing chamber.

The capacity of the extinguishing chamber to break small inductive currents may be improved by arranging one or a plurality of oil pockets around the arc channel.

The accompanying drawing shows an embodiment of the invention. I-n the drawing i1 designates an extinguishing chamber immersed in oil and 2 pressure accumulating chambers filled with loil to a certain level and above the oil gas-lled closed spaces 3. The stationary nozzle-shaped contact 4 is arranged in the upper part of the extinguishing chamber, 5 is a movable contact and 6 an arc channel, through Iwhich the movable contact can 3,100,249 Patented Aug. 6, 1963 ICC be passed to the stationary contact 4. The pressure accumulating chambers 2 communicate through the connecting channels 7 with the arc channel 6. The arc ch-annel communicates with the space outside the extinguishing hamber through the outlet channels 8 and 9 and the pressure unloading channels 10. The channels 9 are displaced about around the arc channel in relation to the channels 8 in order that the arc ames shall not coalesce outside the extinguishing chamber, 111 is an oil level opening arranged in each pressure accumulating chamber so that the oil in this after every breaking action will rise to the same level as before the breaking action. To ensure the breaking of small inductive currents oil pockets 12 have been arranged around the arc channel.

At a breaking action one connecting channel after the other is opened by the movable contact. The gases around the arc generated between the contacts force aside the oil around the arc thereby compressing the gas in the space 3. When the breaking current approaches zero the gas pressure around the arc decreases and the oil in the pressure accumulating chambers I2, the connecting channels of which have been opened, compresses the gases around the arc and forces them out through the channels 8 and 9 at which the arc is extinguished. The length of the arc channel as Iwell as the pressure accumulating chambers 2 and connecting channels 7 arranged after each other along this make the extinguishing chamber especially suited for high voltages because an effectively extinguishing flovsl of gas is obtained along the whole long arc that may be generated between the contacts before an interruption takes place. Due to the -fact that the number of outlet channels 8` and 9 increase in proportion to the length of the arc the pressure in the extinguishing chamber is furthermore held within :reasonable limits.

lI claim:

l. Oil circuit breaker comprising an extinguishing chamber for high voltages immersed in oil and having an inner arcing chamber, said arcing chamber forming a channel through said extinguishing chamber, a stationary conta-ct arranged in one end of said arcing chamber and a movable contact arranged to pass into the1 channel at its other end to engage said stationary contact, means dividing said extinguishing chamber into at least two constant volume pressure accumulating chambers -arranged successively along the arcing chamber, said pressure accumulating chambers each having an oil opening therein so positioned that said chambers are lled with oil only to a predetermined level thus providing a gas-lled and closed space above said oil level, a connecting channel providing communication -between each accumulating chamber and the larcing channel, said arcing chamber having an opening therein land at least one outlet channel connecting said opening in the arcing chamber lwith the oil outside the extinguishing chamber, said opening being uncovered by the movable contact when the contacts separate, said outlet channel being located between two adjacent accumulating chambers.

2. Oil circuit breaker according to claim 1 having outlet channels communicating with openings in the outer wall of the extinguishing chamber, the openings communicating with outlet channels on opposite sides of any accumulating chamber being arranged in diierent planes through the axis of the arcing chamber.

References Cited in the iile of this patent UNITED STATES PATENTS 2,036,800 Ehrenberg et al Apr. 7, 1936 2,714,645 Salzer Aug. 2, 1955 FOREIGN PATENTS 1,017,684 Germany Oct. 17, 1957 1,203,659 France Aug. 3, 1959 

1. OIL CIRCUIT BREAKER COMPRISING AN EXTINGUISHING CHAMBER FOR HIGH VOLTAGES IMMERSED IN OIL AND HAVING AN INNER ARCING CHAMBER, SAID ARCING CHAMBER FORMING A CHANNEL THROUGH SAID EXTINGUISHING CHAMBER, A STATIONARY CONTACT ARRANGED IN ONE END OF SAID ARCING CHAMBER AND A MOVABLE CONTACT ARRANGED TO PASS INTO THE CHANNEL AT ITS OTHER END TO ENGAGE SAID STATIONARY CONTACT, MEANS DIVIDING SAID EXTINGUISHING CHAMBER INTO AT LEAST TWO CONSTANT VOLUME PRESSURE ACCUMULATING CHAMBERS ARRANGED SUCCESSIVELY ALONG THE ARCING CHAMBER, SAID PRESSURE ACCUMULATING CHAMBERS EACH HAVING AN OIL OPENING THEREIN SO POSITIONED THAT SAID CHAMBERS ARE FILLED WITH OIL ONLY TO A PREDETERMINED LEVEL THUS PROVIDING A GAS-FILLED AND CLOSED SPACE ABOVE SAID OIL LEVEL, A CONNECTING CHANNEL PROVIDING COMMUNICATION BETWEEN EACH ACCUMULATING CHAMBER AND THE ARCING CHANNEL, SAID ARCING CHAMBER HAVING AN OPENING THEREIN AND AT LEAST ONE OUTLET CHANNEL CONNECTING SAID OPENING IN THE ARCING CHAMBER WITH THE OIL OUTSIDE THE EXTINGUISHING CHAMBER, SAID OPENING BEING UNCOVERED BY THE MOVABLE CONTACT WHEN THE CONTACTS SEPARATE, SAID OUTLET CHANNEL BEING LOCATED BETWEEN TWO ADJACENT ACCUMULATING CHAMBERS. 